Are electric cars really better for the planet?

Brief Are ElectricOne of the most exciting attributes of electric cars is the fact that they produce no toxic exhaust emissions. Furthermore, if the electricity in the cars comes from renewable sources (as does all the power provided to cars on the Better Place network), customers can rest assured that their driving will always be truly emissions free.

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But what about the energy required to manufacture an electric car? If we were to look at the emissions associated with the vehicle’s total life cycle, “cradle-to- grave”, is an electric car still so green?

A detailed and comprehensive investigation into this question was conducted by a team at EMPA, the Swiss National Laboratories for Materials Science and Technology.1 They compared an electric and an equivalent petrol car, and calculated both the global warming potential (measured in CO2 equivalents) and the total environmental impact of the vehicle’s production and use over its lifetime.2The results were published in a first-class scientific journal, ensuring they were subjected to maximum scrutiny from other experts in the field during the peer review process.

Their results show that the emissions (figure 1) and environmental impact (figure 2) resulting from the manufacture of an electric drivetrain are very similar to those for a petrol drivetrain. (The numbers for the vehicle “glider” are identical, as these do not differ with drivetrain type.)

Whilst the battery does indeed require a significant amount of extra energy and associated emissions for its manufacture, this environmental cost is very quickly paid back in the vehicles’ early driving life. If the electric car is charged using European grid electricity, it produces around half the greenhouse emissions (and less than half the environmental impact) per kilometre driven.3 After 150,000 km, the electric car has resulted in only 62% of the total emissions (and 58% of the total environmental impact) that the petrol car would produce. Of course, if the vehicle is charged using renewable electricity, there are no greenhouse emissions at all associated with its operational life. Likewise, the emissions associated with any vehicle’s manufacture can be reduced by using renewable energy.

 

figure 1 better for planet briefing notes

figure 2 better for planet briefing note

Renault – manufacturer of the Fluence Z.E., the world’s first unlimited range electric car – is installing 450,000 m2 (about 63 football fields’ worth) of solar panels on its factory rooftops generating up to 60 MW of electricity4! These panels will cut Renault’s CO2 emissions by a massive 30,000 tons a year. The EMPA study is not alone: a recent investigation by the British consulting firm Ricardo looked at the same issue, and came to very similar conclusions.5

Controversy erupted when several News Limited publications, including The Times of London and The Australian, skewed the figures in the report and suggested it showed that electric cars weren’t as environmentally friendly as petrol cars – claims which Ricardo vehemently rejected in a sternly worded response.6 At the end of its useful life on the road, a typical car ends up at the scrap yard. Whilst petrol cars have little more to contribute at this point, an electric car’s battery still possesses around 80% of its initial capacity, and can provide many more years of service as stationary energy storage7 after the rest of the car is sold for scrap metal. Thus, in a comprehensive life cycle analysis, electric cars come out far in front of their petrol-powered predecessors, from the cradle to the grave, and even beyond.

References

  1. D.A. Notter, et. al., Contribution of Li-Ion Batteries to the Environmental Impact of Electric Vehicles Environ. Sci. Technol. 2010, 44, 6550-6556
  2. The total environmental impact was calculated using an accepted life cycle analysis (LCA) standard called the Eco-Indicator 99, which takes into account a very broad range of factors, including the energy use and emissions, and also a range of other factors, from the environmental impacts of extracting resources (mining, refining, etc.), right through to damage done to ecosystems and impacts on human health.
  3. Similar results were obtained by Better Place when we calculated and compared the emissions from the petrol-driven Renault Fluence with those from an electric Fluence ZE powered by Australian grid-average electricity. See Better Place Australia technical note, How do the CO2 emissions from an electric car compare to a petrol car? March 2011
  4. http://www.cleantechblog.com/2011/05/renault-60mw-solar-energy.html; http://www.cleanfleetreport.com/clean-fleet-articles/renault-electric-cars-solar-power/;
  5. http://lowcvp.org.uk/assets/reports/RD11_124801_4%20-%20LowCVP%20-%20Life%20Cycle%20CO2%20Measure%20-%20Final%20Report.pdf
  6. http://www.lowcvp.org.uk/assets/news/Response%20to%20Press%20Coverage%20on%20Life%20Cycle%20CO2%20Report.pdf
  7. Better Place Australia technical note,Do Lithium-ion batteries support sustainable electric vehicle driving, January 2011